But I want to use Spotify. To your defence I haven't got Android USB Audio working with Spotify on any Android Phone (tried S4, G2, Z1 Compact) or with any DAC. But hoping to find support for this in the future.

Hi,

You can use Sony Xperia Z2 with all other music apps through usb otg cable, except for picking up call.
I am personally using the Z2 with the IDSD Nano listening to music from TTPod and walkman.

This feature currently seems to be be limited to the Z2 and MAYBE the new flagships from Samsung, HTC and LG.

Thank you for sharing info of the micro iDSD! I own a nano iDSD and I am very satisfied with it. My question is, according to the PCB photo, the micro iDSD utilizes two BB DSD1793 DACs (in dual mono mode), the same as the nano iDSD, why don't you use a higher end model, such as PCM1792/1794/1795? At least those models have better specs, and are more widely used.

Thank you for sharing info of the micro iDSD! I own a nano iDSD and I am very satisfied with it. My question is, according to the PCB photo, the micro iDSD utilizes two BB DSD1793 DACs (in dual mono mode), the same as the nano iDSD, why don't you use a higher end model, such as PCM1792/1794/1795? At least those models have better specs, and are more widely used.

not sure what the exact answer is, but i think iFi mentioned in a post somewhere that they tried a whole bunch of different chips and the one they settled on was the one they thought sounded the best. so specs are one thing, but sound is another...

But I want to use Spotify. To your defence I haven't got Android USB Audio working with Spotify on any Android Phone (tried S4, G2, Z1 Compact) or with any DAC. But hoping to find support for this in the future.

Hi,

You can use Sony Xperia Z2 with all other music apps through usb otg cable, except for picking up call.
I am personally using the Z2 with the IDSD Nano listening to music from TTPod and walkman.

This feature currently seems to be be limited to the Z2 and MAYBE the new flagships from Samsung, HTC and LG.

Hi thanks for the info. Just tried iDSD Nano with Galaxy S5 (4.4.2), USB Audio out and Spotify. And it works, awesome!

So hopefully iDSD Micro will support this as well. Looks like it is going to be a killer product.

Thank you for sharing info of the micro iDSD! I own a nano iDSD and I am very satisfied with it. My question is, according to the PCB photo, the micro iDSD utilizes two BB DSD1793 DACs (in dual mono mode), the same as the nano iDSD, why don't you use a higher end model, such as PCM1792/1794/1795? At least those models have better specs, and are more widely used.

There's a lot more to the sound of a DAC than just which DAC chip is used.

The chosen chip plays PCM natively and also plays DSD natively.

What do you mean by better specs? 32 bit perhaps? This is only relevant if you want to implement digital volume control. The iDSD uses an analogue stepped attenuator so a 32 bit DAC is not needed. 24 bits is plenty given that the performance of the analogue circuitry rarely exceeds 20 bits anyway.

There's a lot more to the sound of a DAC than just which DAC chip is used.

The chosen chip plays PCM natively and also plays DSD natively.

What do you mean by better specs? 32 bit perhaps? This is only relevant if you want to implement digital volume control. The iDSD uses an analogue stepped attenuator so a 32 bit DAC is not needed. 24 bits is plenty given that the performance of the analogue circuitry rarely exceeds 20 bits anyway.

What has 'widely used' got to do with it?

As for the "better specs", I mean those chips have better SNR, dynamic range, THD+N, etc.

If some chips are widely used by high-end devices, I think they are proven to have decent sound. I might be wrong.

There's a lot more to the sound of a DAC than just which DAC chip is used.

The chosen chip plays PCM natively and also plays DSD natively.

What do you mean by better specs? 32 bit perhaps? This is only relevant if you want to implement digital volume control. The iDSD uses an analogue stepped attenuator so a 32 bit DAC is not needed. 24 bits is plenty given that the performance of the analogue circuitry rarely exceeds 20 bits anyway.

What has 'widely used' got to do with it?

What do you mean by natively? All the DACs I mentioned are advanced segment DAC with DSD/PCM interface. There is no difference between DSD1793 (PCM1793) and PCM1792 in their functional block diagrams, except the latter have better dynamic range (113dB vs 132dB), lower THD+N (0.001% vs 0.0004%) and so on.

What do you mean by natively? All the DACs I mentioned are advanced segment DAC with DSD/PCM interface. There is no difference between DSD1793 (PCM1793) and PCM1792 in their functional block diagrams, except the latter have better dynamic range (113dB vs 132dB), lower THD+N (0.001% vs 0.0004%) and so on.

By 'natively' I mean bit perfect without upsampling or conversion.

You got your distortion figures back to front there. The DSD1793 is lowest at .0004%.

The datasheet shows that the chip contains an upsampling digital filter module.

The datasheet also shows that there is an interface for external upsampling and filtering.

Guess which one iFi uses

On THD+N, the datasheet says 0.001% but the TI website says 0.0004%. Seems like the TI media cannot be relied upon here. Of course, 0.001% is still a very good figure.

Without wishing to patronise, I suggest searching out and reading all the iFi postings in this thread as there is a lot more information given about the choices of chips and of the digital filtering or lack thereof.

The recent discussion about chipsets and what constitutes what prompted us to bring in part 4 of the Software Design Notes. (also the AudioStream interview is quite heavy going as Thorsten does like the details).

Software Design Notes (4)

DSD – No ordinary DSD

There is DSD playback and DSD by iFi which we believe is different.

Normal DSD:

iFi DSD：

We are really pleased with our DSD implementation - it really is quite one of the most original DSD implementations out there. At the core, no data conversion and manipulation is done INSIDE this chip, so the DSD data is preserved Bit-Perfectly. An analogue filter is applied to the DSD data before it is sent to the output stage.

For us, "doing digital" means keeping the signal path original as much as possible; ideally from the ADC being DSD kept through to DAC being DSD (the same of course goes for PCm which we will cover later).

But in the case of the nano iDSD and micro iDSD, we have this:

Therefore, when playing back an originally-recorded DSD file through this Burr-Brown chipset on the iDSD, the listener has ensured that the WHOLE ADC > DAC path has remained native” in its DSD format. Like this:

The DSD chip we use is under full software control in order to gain access to many “undocumented features” (yes, they all have them). What are those “undocumented features”, we will announce them (a few should be a world’s first) closer to when we officially launch the micro iDSD.

Compared to the lion’s share of DSD-capable chips out there, most of them perform data conversion and manipulation of the DSD data and hence are no longer Bit-Perfect. This maybe the designer's choice, which is very much their prerogative but for us, we just about make it our mission to avoid such conversion processes.

Why? - conversion from one format to another is lossy. Hence to us, this is best avoided as much as possible.

What is the giveaway? If they do digital volume control on the DSD stream, this is very likely to convert the DSD data into NON-DSD data (does not necessary mean that they are converting into PCM, but converting into something non-DSD at the very least).

Even Pro Audio Studios use DAWs that convert

Pyramix do not even pretend to use DSD, in their DAW any processing means the DSD signal is converted to DXD (24Bit/352.8KHz) and processed as this, then converted back to DSD.

And Sonoma converts to DSD wide (aka PCM narrow), then applies a 24Bit scaling factor, ending up with 32PCM which is then converted back to DSD (remodulated from PCM).

It means that any processing of DSD in either Sonoma or Pyramix converts DSD to a form of PCM. Only "Tape Splice" (this refers to physically cutting the old magnetic tape and splicing two different tapes together) style edits can be done while retaining DSD.

If these VERY expensive DAW (Digital Audio Workstation) music recording/production packages cannot fade/volume control DSD without turning it to PCM, this begs the question of how come mainstream and far less costly commodity DAC's chipsets can?

This comes full circle back to why we selected the Burr-Brown chipset AND central to this why we use an analogue volume control (which yes, also has its issues but to us, these are far less sonically-damaging).

The recent discussion about chipsets and what constitutes what prompted us to bring in part 4 of the Software Design Notes. (also the AudioStream interview is quite heavy going as Thorsten does like the details).

Software Design Notes (4)

DSD – No ordinary DSD

But in the case of the nano iDSD and micro iDSD, we have this:

Therefore, when playing back an originally-recorded DSD file through this Burr-Brown chipset on the iDSD, the listener has ensured that the WHOLE ADC > DAC path has remained native” in its DSD format. Like this:

The DSD chip we use is under full software control in order to gain access to many “undocumented features” (yes, they all have them). What are those “undocumented features”, we will announce them (a few should be a world’s first) closer to when we officially launch the micro iDSD.

Mr. iFi audio,

Can you please help me understand how the timing is handled in block two of the first image and in the DAC conversion section within the second image? Is a single clock used? Multiple clocks for DSD and PCM? What about multiples of 44.1 kHz and 48 kHz?

My apologies if this has all been answered already in this thread. Thank you.

Without wishing to patronise, I suggest searching out and reading all the iFi postings in this thread as there is a lot more information given about the choices of chips and of the digital filtering or lack thereof.

I'm trying to put all tech info we got from iFi in one doc.
Can I post it here then (kind of attachment?)